The crop-selective, herbicidal agent 1-{[o-(cyclopropylcarbonyl) phenyl]sulfamoyl}-3-(4,6-dimethoxy-2-pyrimidinyl) urea is described in U.S. Pat. No. 5,009,699. This unique sulfamoyl urea derivative demonstrates a superior margin of safety toward crop plants, especially rice plants, while concomitantly controlling troublesome broadleaf weeds and sedges.
The compound, 4-halo-2'-nitrobutyrophenone, and its preparation via the reaction of dihydro-3-(o-nitrobenzoyl)-2(3H)-furanone and hydrogen halide is described in U.S. Pat. No. 4,075,346. This patent describes the use of 4-halo-butyrophenone in the preparation of 4-(secondaryamino)-butyrophenone derivatives and their use as central nervous system depressants. It has now been found that 4-halo-2'-nitrobutyrophenone may be employed as a precursor to o-nitrophenylcyclopropyl ketone, a key intermediate in the manufacture of the crop-selective, herbicidal agent 1-{[(o-(cyclopropylcarbonyl)phenyl]sulfamoyl}-3-(4,6-dimethoxy-2-pyrimidin yl) urea.
It is an object of this invention to provide a key intermediate in the manufacture of this important crop-selective herbicidal agent.
It is another object of this invention to provide an efficient and integrated method for the preparation of this key intermediate.
It is a further object of this invention to provide a method of preparation for o-aminophenyl cyclopropyl ketone, also an important intermediate compound in the preparation of 1-{[o-(cyclopropylcarbonyl)phenyl]sulfonyl}-3-(4,6-dimethoxy-2-pyrimidinyl ) urea.